/Engine/Source/Runtime/MovieScene/Public/Evaluation/MovieSceneSequenceHierarchy.h
Find the sub sequence for a given sequence ID, or nullptr if it was not found
pointer to the sequence, or nullptr if the sequence ID does not exist in this hierarchy
[UMovieSceneSequence](API\Runtime\MovieScene\UMovieSceneSequence) * FindSubSequence ( FMovieSceneSequenceIDRef SequenceID ) const